Ruth Francis-Floyd

COMPARISON OF METHODS USED TO DIAGNOSE GENERALIZED INFLAMMATORY DISEASE IN MANATEES (TRICHECHUS MANATUS LATIROSTRIS)

Abstract Manatees (Trichechus manatus latirostris) are afflicted with inflammatory and infectious disease secondary to human interaction, such as boat strike and entanglement, as well as “cold stress syndrome” and pneumonia. White-blood-cell count and fever, primary indicators of systemic inflammation in most species, are insensitive in diagnosing inflammatory disease in manatees. Acute phase-response proteins, such as haptoglobin and serum amyloid A, have proven to be sensitive measures of inflammation/infection in domestic large animal species. This study assessed diagnosis of generalized inflammatory disease by different methods including total white-blood-cell count, albumin: globulin ratio, gel electrophoresis analysis, C-reactive protein, alpha1 acid glycoprotein, haptoglobin, fibrinogen, and serum amyloid A. Samples were collected from 71 apparently healthy and 27 diseased animals during diagnostic medical examination. Serum amyloid A, measured by ELISA, followed by albumin:globulin ratio, measured by plasma gel electrophoresis, were most sensitive in diagnosing inflammatory disease, with diagnostic sensitivity and specificity of approximately 90%. The reference interval for serum amyloid A is <10–50 μg/ml with an equivocal interval of 51–70 μg/ml. The reference interval for albumin:globulin ratio by plasma gel electrophoresis is 0.7–1.1. Albumin: globulin ratio, calculated using biochemical techniques, was not accurate due to overestimation of albumin by bromcresol green dye-binding methodology. Albumin:globulin ratio, measured by serum gel electrophoresis, has a low sensitivity of 15% due to the lack of fibrinogen in the sample. Haptoglobin, measured by hemoglobin titration, had a reference interval of 0.4–2.4 mg/ml, a diagnostic sensitivity of 60%, and a diagnostic specificity of 93%. The haptoglobin assay is significantly affected by hemolysis. Fibrinogen, measured by heat precipitation, has a reference interval of 100–400 mg/dl, a diagnostic sensitivity of 40%, and a diagnostic specificity of 95%.

Spironucleus vortens n. sp. from the freshwater angelfish Pterophyllum scalare: morphology and culture.

ABSTRACT. A new diplomonad flagellate, Spironucleus vortens n. sp., is described from the intestinal lumen of the freshwater angelfish, (Pterophyllum scalare), bred in Florida. Live organisms are pyriform, and measure 12.5–20.5 μm long by 5.0–11.2 üm wide. Scanning electron microscopy shows that the trophozoite bears two compound lateral longitudinal ridges, each originating posterior to three emerging anterior flagella, and continuing posteriorly to the emergence of the posterior flagellum. Each ridge comprises a broad central part, surrounded by a peripheral ridge. At the opening of the flagellar pocket, the broader right peripheral ridge crosses to the other side of the body, and then back again. The posterior end of the body bears two papillae. Transmission electron microscopy shows that the compound lateral ridges are supported by microtubules, and bear microfibrillar structures in discrete longitudinal plaques. The serendipitous growth of S. vortens in a culture system with lip tumor tissue, facilitated axenic cultivation in a modified TYM medium (trypticase, yeast extract, maltose). The flagellate is now routinely maintained in an axenic TYI‐S‐33 medium (trypticase, yeast extract, iron serum), and is stabilized in the cryopreserved state. Spironucleus vortens is an aerotolerant anaerobe that can be cultured at 25° C, 28° C and 30° C.

An Epizootic of Edwardsiella tarda in Largemouth Bass (Micropterus salmoides)

Edwardsiella tarda, an opportunistic bacterial pathogen, was isolated from dying largemouth bass (Micropterus salmoides) during an epizootic in a eutrophic lake system, Lochloosa Lake, Florida, USA. Approximately 1,500 adult fish died over a 6-wk period during the late summer and early fall of 1991. A mixed population of aerobic bacteria (E. tarda, Aeromonas hydrophila, and Pseudomonas sp.) was isolated from deep cutaneous ulcers and intestines of moribund bass. However, E. tarda in pure culture was the only bacterium isolated from several viscera of several fish; E. tarda may be the etiologic agent responsible for some episodes of seasonal mortality in largemouth bass.

Nitrate‐Induced Goiter in Captive Whitespotted Bamboo Sharks Chiloscyllium plagiosum

Elasmobranch susceptibility to goiter formation in captive environments has been well documented. Until recently, most public aquariums operated under the belief that the etiology of goiter in elasmobranchs was nutritional and specifically caused by insufficient dietary iodine. Recent studies have demonstrated that high environmental nitrate (NO3-N) inhibits the ability of the thyroid gland to utilize available iodide, resulting in thyroid gland overstimulation by thyroid stimulating hormone and ultimately leading to the development of goiter. The objective of this study was to evaluate the effects of high environmental nitrate concentrations on thyroid function in juvenile whitespotted bamboo sharks Chiloscyllium plagiosum. In July 2008, five juveniles (80-150 g) were exposed to a low-nitrate environment (NO3-N concentration < 1 mg/L of water) and five were exposed to an elevated-nitrate environment (NO3-N = 70 mg/L) for 29 d in a flow-through natural seawater system. Nitrate exposure did not affect growth rates (e.g., weight, length, and condition factor) and did not alter free plasma thyroxine concentrations during the 29-d experimental period. However, histological examination of thyroid glands from sharks exposed to elevated nitrate revealed the development of diffuse hyperplastic goiter. With increasing restrictions on water use, most modern aquaria operate as recirculating systems, which results in higher and more chronic nitrate exposure for captive animals. Goiter is one of the most common health problems in captive elasmobranchs, and this study suggests that nitrate exposure is an important factor in the etiology of this disease.

Use of Bayluscide (Bayer 73) for Snail Control in Fish Ponds

Abstract Bayluscide applied to ponds on two commercial fish farms at five rates (from L1 to 13.5 kilogram per surface hectare) effectively controlled aquatic snails. Laboratory toxicity tests confirmed susceptibility of three endemic species of aquatic snail—Melanoides tuberculatus, Physella hendersoni, and Planorbella duryi—to Bayluscide. Observed 24-h concentrations lethal to 50% of snails (LC50) ranged from 0.062 to 0.085 mg/L, and 24-h concentrations lethal to 99% of snails (LC99) ranged from 0.149 to 0.440 mg/L. The 24-h LC50 concentrations for nontarget organisms were 0.198 mg/L for anuran tadpoles Scaphiopus holbrooki and Rana catesbeiana, 0.657 mg/L for eastern mosquitofish Gambusia holbrooki, and 4.909 mg/L for turtles Trachemys scripta. No adverse effects were observed in crayfishes Procambarus alleni and P. paeninsulanus exposed to 10 mg/L for 24 h. After Bayluscide application of L 1 kg/ha to a 0.06-ha pond in an environmental fate study, concentrations were detected in pond water at ranges 0....

Molecular and immunohistochemical diagnosis of Francisella noatunensis subsp. orientalis from formalin-fixed, paraffin-embedded tissues

Members of the genus Francisella (viz., F. noatunensis subsp. orientalis [Fno] and F. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. In the present study, 68 archived formalin-fixed, paraffin-embedded (FFPE) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detection of the Fno intracellular growth loci C (iglC) gene and by immunohistochemistry for the demonstration of Fno antigens. The results revealed a high correlation between these 2 diagnostic techniques validating their use for the diagnosis of Fno infection in archived FFPE tissues and confirming the presence of Fno in fish species from the Cari y years of the present century.

Megalocytivirus infection in orbiculate batfish Platax orbicularis

Megalocytiviruses cause systemic disease in both marine and freshwater fishes, negatively impacting ornamental and food fish aquaculture. In this report, we characterize a megalocytivirus infection in a captive marine ornamental fish, the orbiculate batfish Platax orbicularis. Histologic examination revealed cytomegalic cells characterized by strongly basophilic granular intracytoplasmic inclusions within various organs. Transmission electron microscopy revealed icosahedral virus particles within the cytoplasm of cytomegalic cells consistent with an iridovirus infection. Analysis of the major capsid protein gene sequence confirmed that the orbiculate batfish virus is a member of the family Iridoviridae and is identical to the only other megalocytivirus reported from a marine ornamental fish, the Banggai cardinalfish Pterapogon kauderni iridovirus.

USE OF BLOOD CULTURE AS A NONLETHAL METHOD FOR ISOLATING BACTERIA FROM FISH

Abstract Simple nonlethal blood culture methodology, an alternative to euthanasia for diagnosing systemic bacterial infections in fish, is described. Blood was extracted from the caudal vein of 20 individuals of five fish species, incubated in brain–heart infusion broth, and then plated onto enriched blood agar. Nine of these fish were subsequently euthanized and necropsied for confirmatory tissue cultures. Five species of bacteria were isolated from the blood cultures from nine fish, and the tissue culture results in euthanized, necropsied fish agreed with the blood culture results in all cases. All the fish that were not euthanized survived for 24 hr, although two heavily parasitized fish subsequently died.

Clinical Examination of Fish in Private Collections

The rapid advancement of fish medicine over the past 10 years has led to a drastically improved ability to manage the individual pet fish successfully. Principle physiologic differences between fish and higher vertebrates include the lack of ability to regulate body temperature (this has a profound effect on the immune system), the use of gills for respiration, and the importance of osmoregulation in the aquatic environment. Components of the clinical history for a fish patient should include information on the environment, tank mates, recent medical history, and specific information on the affected individual. Fish can be manually restrained or safely anesthetized with methane tricaine sulfonate, depending on their size, condition, and circumstances. Diagnostic techniques useful for fish patients include gill, skin, and fin biopsy; hematology; cytology; radiology; and ultrasound. Preventive medicine programs should include water quality, nutritional management, sanitation, and quarantine.

THE ONSET OF GOITER IN SEVERAL SPECIES OF SHARKS FOLLOWING THE ADDITION OF OZONE TO A TOUCH POOL

This report describes the onset of goiter in several species of shark following the addition of ozone to a touch pool. A detailed description of a female brown-banded bamboo shark (Chiloscyllium punctatum) that was presented with multinodular goiter is provided. Four other brown-banded bamboo sharks and 11 white-spotted bamboo sharks (Chiloscyllium plagiosum) housed in the same system developed clinical disease consistent with goiter, but two zebra bullhead sharks (Heterodontus zebra) did not. Plasma thyroxine (T4) concentration was 4.64 ng/ml before euthanasia, consistent with a diagnosis of hypothyroidism. The sharks had been chronically exposed to mean (+/- standard error) NO3-N concentrations of 35 +/- 5.12 mg/L before ozonation of the system. Ozonation of aquarium water causes a reduction in environmental iodide, which is required for thyroid hormone synthesis. Nitrate is goitrogenic and would further decrease I- absorption by competitive inhibition. Multinodular goiter is consistent with goiter caused by chronic iodide deficiency. Understanding the interaction between water chemistry and goiter development is critical to development of elasmobranch health management systems.